Travel Demand ? the Influence on Commuter Distances of Labour Supply/demand Imbalances
I Williams, WSP Cambridge, UK
This examines the changes over time and across space in the pattern of demand for travel, particularly for travel to work. It focuses on the main influences on average distance travelled.
This examines changes over time and across space in travel demand patterns, particularly the average distance travelled to work. GIS mapping tools are used to illustrate the empirical evidence on commuter travel patterns.
Firstly, it analyses travel demand summed over all trip purposes, using data for Great Britain from the National Travel Survey to illustrate the differences in the total kilometres travelled per week for those living in urbanisations of different sizes, and with different social structures. This shows that the smaller the settlement size the greater the overall distance travelled and the greater the proportion of this distance that is travelled by car. The influence of the demographic / socio-economic profile of the residents is separated out from the spatial impacts, demonstrating that both are significant in determining travel demand. The analysis also demonstrates that whereas the total annual number of trips and the total travel time for a given type of person show little trend through the years, in contrast the total distance travelled has increased systematically.
Then it examines the pattern of a specific trip purpose, travel to work, in more detail using the GB Censuses of 1991 and 2001. The modal pattern of commuting has changed over the decade in different ways between London and its surrounding region. For London residents, car is losing market share, whereas outside London it is gaining share. Average commuting distances have grown continuously in the past, though they continue to differ markedly between the sexes, between part and full-time workers, between industry types and between locations. The reasons underlying these spatial and industry type variations have been investigated. They are strongly linked to imbalances between the local supply of labour and the demand for labour of a given labour type and to the extent to which jobs in some industries agglomerate into a few locations and in others are comparatively ubiquitous. Land use policies to reduce the demand for travel should take such effects into account. The degree of skill specialisation of jobs is another influence on average trip length, though this is also correlated with the influence of income.
The presentation will draw heavily on GIS mapping tools to illustrate the empirical evidence on the spatial differences over the years in commuter travel patterns, both at the workplace and the residence end.
Association for European Transport